GSTM1 and neoplasm: For T2 disease, on multivariate analysis, LC was adversely affected by poorly differentiated grading (HR: 4.3, p = 0.022), Hb < 13.0 (HR: 3.78, p = 0.031), subglottic extension (HR: 2.15, p = 0.027) and tumor BED Gy15 < 65.0 Gy15 (HR: 1.8, p = 0.038).